Tweakable effects (and more!)

[xxjetterxx]

Hi guys, seeing as tweakables are coming, I'd like to share my ideas.

-Afterburners.

After doing some research, I found this page : http://science.howstuffworks.com/transport/flight/modern/question374.htm And I thought "wow, that'd be nice in KSP!"

So perhaps we could have an action group toggle, and a tweakable to add afterburner to jet engine (thus adding more mass, and reducing the ISP of the engine,

but increasing the thrust by 50% or more, and having the afterburners flame-out if the air goes too low (afterburners use excess oxygen from the intakes.)

-Different fuels = different effects.

Perhaps we could get a selection of fuels to choose from. for example, Kerosene, LiquidFuel, RP-1, and LOX. these different fuels would be

heavier, lighter, more efficient, less efficient, etc. maybe even special fuels for nuke engines, with drastic changes. (solid core or gas core, for example.)

-Maybe an IVA update?

As we all know, the IVA's are incomplete. Personally, I think it would be nice to have IVA for the "shuttle" cockpit (the big plane one) and for the inline jet cockpit (not the pointy one, the one you have to put nosecones on. It's essentially just a brown can inside there.)

Thanks for reading guys, hopefully SQUAD will see this and take some into consideration.

[Supernovy]

AFAIK, the two spaceplane cockpits you mention are going to be completely replaced at some point, so giving them an IVA before then would be wasted effort, not to mention that more IVA views is on the what not to suggest list.

[UberFuber]

-Afterburners.

After doing some research, I found this page : http://science.howstuffworks.com/transport/flight/modern/question374.htm And I thought "wow, that'd be nice in KSP!"

So perhaps we could have an action group toggle, and a tweakable to add afterburner to jet engine (thus adding more mass, and reducing the ISP of the engine,

but increasing the thrust by 50% or more, and having the afterburners flame-out if the air goes too low (afterburners use excess oxygen from the intakes.)

Regarding added mass, afterburn system advantage is that it doesn't add much mass (likely negligible compared to the engine itself) for the added thrust it gives. So the mass differences is likely negligible.

-Different fuels = different effects.

Perhaps we could get a selection of fuels to choose from. for example, Kerosene, LiquidFuel, RP-1, and LOX. these different fuels would be

heavier, lighter, more efficient, less efficient, etc. maybe even special fuels for nuke engines, with drastic changes. (solid core or gas core, for example.)

Special fuel for nuke engines is already planned and stated in the later dev blogs.

Regarding different fuel types, there's likely not enough differences between them to justify the added complexity of modeling different fuel types.

[Wahgineer]

Special fuel for nuke engines is already planned and stated in the later dev blogs.

Regarding different fuel types, there's likely not enough differences between them to justify the added complexity of modeling different fuel types.

ARRGH! Why does everyone get it wrong with the fuel?!?!

Everyone thinks that the LV-Ns will run on Blutonium: That is a common misconception. The Blutonium will be used as the catalyst to ignite regular fuel, which is what the real life NERVAs would have run on. The LV-Ns will use tanks of regular fuel, not tanks of solid radioactive elements. Yes, Blutonium will need to be replaced, but only after 7-8 round trips to JOOL, where as the tank(s) of regular fuel will have to be gassed up after every trip or so. RTGs will also run on Blutonium, but should last WAAAYYY longer then the Blutonium in an LV-N.

NERVA/LV-N 101: the engine runs on fuel, the Plutonium/Blutonium is used in the reactor that iginites the fuel.

[RadHazard]

KSP Intersteller has a pretty good model of nuclear thermal rockets (which is what the LV-N is). The reactors have nuclear fuel that lasts multiple years, and the rocket nozzles run by expelling reaction mass like liquid fuel out the back. The stock tweakables system could be similar to that, where it would allow you to change the reaction mass the LV-N uses. (such as between pure liquid fuel and L/OX, both of which I believe were considered for real-life nuclear thermal rockets)

[UberFuber]

ARRGH! Why does everyone get it wrong with the fuel?!?!

Everyone thinks that the LV-Ns will run on Blutonium: That is a common misconception. The Blutonium will be used as the catalyst to ignite regular fuel, which is what the real life NERVAs would have run on. The LV-Ns will use tanks of regular fuel, not tanks of solid radioactive elements. Yes, Blutonium will need to be replaced, but only after 7-8 round trips to JOOL, where as the tank(s) of regular fuel will have to be gassed up after every trip or so. RTGs will also run on Blutonium, but should last WAAAYYY longer then the Blutonium in an LV-N.

NERVA/LV-N 101: the engine runs on fuel, the Plutonium/Blutonium is used in the reactor that iginites the fuel.

Correct on that it consumes liquid and not solid radioactive source from external tank.

Incorrect on that the nuclear core "ignite" regular fuel. Although the current in-game NERVA do seems to behave that way (super-heat fuel and oxidizer to combust them), but the developer did put in a comment in the config file that this is currently due to limitation in their system and that they'll change it.

My statement on special fuel doesn't mean that its running off radioactive solids.

From what the game implies, the liquid fuel in question seems to be some sort of jet-fuel instead of liquid hydrogen due to the fact that jet-engine can use it without problem (and normal rockets CAN operate off jet-fuel).

NERVA just need some sort of working fluid that it can heat-up/vaporize to provide thrust, hence the reason why it doesn't/shouldn't require oxidizer. It just so happen that the most efficient working fluid, liquid hydrogen, also works very well as a rocket fuel. NERVA can probably work off jet-fuel (and/or jet-engine could work off liquid hydrogen) to simplify things for gameplay purposes. But the difference in fuel type could further differentiate between NERVA, liquid-fuel engine, and jet-engine.

Jet Fuel: Less Isp when burned, but tank weighs less (no need for cryogenic refrigeration).

Liquid Hydrogen: High Isp when burned, but tank weighs more (need cryogenic refrigeration) and/or require constant electrical requirement to prevent it from overheating.

Jet-Engine: Can operate off jet-fuel only.

Liquid Rocket Engine: Can operate off both Liquid Hydrogen or Jet Fuel (lower Isp when using the latter).

NERVA: Can operate off Liquid Hydrogen only.

Edited November 22, 2013 by UberFuber

[Eric S]

Although the current in-game NERVA do seems to behave that way (super-heat fuel and oxidizer to combust them), but the developer did put in a comment in the config file that this is currently due to limitation in their system and that they'll change it.

Correct, the limitation is that currently, they'd need to duplicate all the fuel tank parts in "fuel only" variants. The devs have stated that they plan on changing the way the Atomic Rocket Engine so that it only uses fuel, no oxidizer, when they add the tweakables, as that will let them have "fuel only" fuel tanks without needing multiple parts. And coincidentally, tweakables are planned for 0.23, so we could be seeing this change to the LV-N very soon.

Also, there were variants on the atomic rocket engine idea that did "consume" the radioactive materials, I believe those were referred to as various types of "open cycle" engines, as opposed to "closed cycle" variants, so that may be an additional source of confusion on the subject.

Edited November 22, 2013 by Eric S

[UberFuber]

Correct, the limitation is that currently, they'd need to duplicate all the fuel tank parts in "fuel only" variants. The devs have stated that they plan on changing the way the Atomic Rocket Engine so that it only uses fuel, no oxidizer, when they add the tweakables, as that will let them have "fuel only" fuel tanks without needing multiple parts. And coincidentally, tweakables are planned for 0.23, so we could be seeing this change to the LV-N very soon.

That's what I believe I've heard before. Although I wonder if they'll use the Tweakable system to differentiate between Jet-fuel (used by jet-engine) and liquid hydrogen (used by rocket engine and NERVA). Of course, they might just leave it as "fuel" to simplify it all.

[Eric S]

That's what I believe I've heard before. Although I wonder if they'll use the Tweakable system to differentiate between Jet-fuel (used by jet-engine) and liquid hydrogen (used by rocket engine and NERVA). Of course, they might just leave it as "fuel" to simplify it all.

Yeah, I expect they'll leave the unified fuel alone, they haven't shown too much interest in that level of detail in the past.

[Wahgineer]

Correct on that it consumes liquid and not solid radioactive source from external tank.

Incorrect on that the nuclear core "ignite" regular fuel.

1: Thank god that somebody knows how NERVA engines work.

2: I used 'ignite' for the lack of a better word. 'Super heat' seems more accurate.

About the rest of your post:

Both jets and rocket engines (in the game) use liquid fuel for simplicity. We don't need two separate fuels to do virtually the same job.

[meve12]

A "generator" tweak-able option for NERVAs, which converts it into a mere nuclear reactor.(Produces lots of electricity, does not use fuel, only blutonium.) Might be useful when resources come along, since you'll have to power those drills somehow.

And also a "turbine" option that does almost the same for jet/rocket engines(uses fuel, and intakes/oxidizier depending on engine to make electricity.) Good for early game power gen, but watch the fuel....

[Wahgineer]

A "generator" tweak-able option for NERVAs, which converts it into a mere nuclear reactor.(Produces lots of electricity, does not use fuel, only blutonium.) Might be useful when resources come along, since you'll have to power those drills somehow.

And also a "turbine" option that does almost the same for jet/rocket engines(uses fuel, and intakes/oxidizier depending on engine to make electricity.) Good for early game power gen, but watch the fuel....

1. That's what the RTGs are for

2. Almost all of the engines have alternators for generating power. If you're talking about using fuel+oxidizer to create electricity without the engine running, the devs at some point want to add fuel cells, which generates electricity and produces water as a byproduct.

[meve12]

I figured nuclear reactors would provide a lot more power, but actually consume blutonium. RTGs are low power, long lifespan generators.

Fuel cells might work, although I'd also like a generator that runs with intake air.

[S4qFBxkFFg]

(I am not a nuclear scientist.)

meve12 has it right, nuclear reactors do consume the nuclear fuel (but in the basic type, not at any rate even close to what a fossil fuel would be consumed) while in RTGs the fuel just decays, and the heat is used to generate electricity - see https://en.wikipedia.org/wiki/Thermoelectric_effect for the details.

It's probably possible to design a reactor which outputs electricity even when not producing thrust - I'm not sure how much weight that would save over just using a nuclear engine and an RTG.